# =================================================================== # # Copyright (c) 2014, Legrandin # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in # the documentation and/or other materials provided with the # distribution. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE # POSSIBILITY OF SUCH DAMAGE. # =================================================================== import os import re import unittest from binascii import hexlify from Crypto.Util.py3compat import b, tobytes, bchr, unhexlify from Crypto.Util.strxor import strxor_c from Crypto.Util.number import long_to_bytes from Crypto.SelfTest.st_common import list_test_cases from Crypto.Cipher import AES from Crypto.Hash import SHAKE128 def get_tag_random(tag, length): return SHAKE128.new(data=tobytes(tag)).read(length) class OcbTests(unittest.TestCase): key_128 = get_tag_random("key_128", 16) nonce_96 = get_tag_random("nonce_128", 12) data_128 = get_tag_random("data_128", 16) def test_loopback_128(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) pt = get_tag_random("plaintext", 16 * 100) ct, mac = cipher.encrypt_and_digest(pt) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) pt2 = cipher.decrypt_and_verify(ct, mac) self.assertEqual(pt, pt2) def test_nonce(self): # Nonce is optional AES.new(self.key_128, AES.MODE_OCB) cipher = AES.new(self.key_128, AES.MODE_OCB, self.nonce_96) ct = cipher.encrypt(self.data_128) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) self.assertEqual(ct, cipher.encrypt(self.data_128)) def test_nonce_must_be_bytes(self): self.assertRaises(TypeError, AES.new, self.key_128, AES.MODE_OCB, nonce='test12345678') def test_nonce_length(self): # nonce cannot be empty self.assertRaises(ValueError, AES.new, self.key_128, AES.MODE_OCB, nonce=b("")) # nonce can be up to 15 bytes long for length in range(1, 16): AES.new(self.key_128, AES.MODE_OCB, nonce=self.data_128[:length]) self.assertRaises(ValueError, AES.new, self.key_128, AES.MODE_OCB, nonce=self.data_128) def test_block_size_128(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) self.assertEqual(cipher.block_size, AES.block_size) # By default, a 15 bytes long nonce is randomly generated nonce1 = AES.new(self.key_128, AES.MODE_OCB).nonce nonce2 = AES.new(self.key_128, AES.MODE_OCB).nonce self.assertEqual(len(nonce1), 15) self.assertNotEqual(nonce1, nonce2) def test_nonce_attribute(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) self.assertEqual(cipher.nonce, self.nonce_96) # By default, a 15 bytes long nonce is randomly generated nonce1 = AES.new(self.key_128, AES.MODE_OCB).nonce nonce2 = AES.new(self.key_128, AES.MODE_OCB).nonce self.assertEqual(len(nonce1), 15) self.assertNotEqual(nonce1, nonce2) def test_unknown_parameters(self): self.assertRaises(TypeError, AES.new, self.key_128, AES.MODE_OCB, self.nonce_96, 7) self.assertRaises(TypeError, AES.new, self.key_128, AES.MODE_OCB, nonce=self.nonce_96, unknown=7) # But some are only known by the base cipher # (e.g. use_aesni consumed by the AES module) AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96, use_aesni=False) def test_null_encryption_decryption(self): for func in "encrypt", "decrypt": cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) result = getattr(cipher, func)(b("")) self.assertEqual(result, b("")) def test_either_encrypt_or_decrypt(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.encrypt(b("xyz")) self.assertRaises(TypeError, cipher.decrypt, b("xyz")) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.decrypt(b("xyz")) self.assertRaises(TypeError, cipher.encrypt, b("xyz")) def test_data_must_be_bytes(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) self.assertRaises(TypeError, cipher.encrypt, 'test1234567890-*') cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) self.assertRaises(TypeError, cipher.decrypt, 'test1234567890-*') def test_mac_len(self): # Invalid MAC length self.assertRaises(ValueError, AES.new, self.key_128, AES.MODE_OCB, nonce=self.nonce_96, mac_len=7) self.assertRaises(ValueError, AES.new, self.key_128, AES.MODE_OCB, nonce=self.nonce_96, mac_len=16+1) # Valid MAC length for mac_len in range(8, 16 + 1): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96, mac_len=mac_len) _, mac = cipher.encrypt_and_digest(self.data_128) self.assertEqual(len(mac), mac_len) # Default MAC length cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) _, mac = cipher.encrypt_and_digest(self.data_128) self.assertEqual(len(mac), 16) def test_invalid_mac(self): from Crypto.Util.strxor import strxor_c cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) ct, mac = cipher.encrypt_and_digest(self.data_128) invalid_mac = strxor_c(mac, 0x01) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) self.assertRaises(ValueError, cipher.decrypt_and_verify, ct, invalid_mac) def test_hex_mac(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) mac_hex = cipher.hexdigest() self.assertEqual(cipher.digest(), unhexlify(mac_hex)) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.hexverify(mac_hex) def test_message_chunks(self): # Validate that both associated data and plaintext/ciphertext # can be broken up in chunks of arbitrary length auth_data = get_tag_random("authenticated data", 127) plaintext = get_tag_random("plaintext", 127) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(auth_data) ciphertext, ref_mac = cipher.encrypt_and_digest(plaintext) def break_up(data, chunk_length): return [data[i:i+chunk_length] for i in range(0, len(data), chunk_length)] # Encryption for chunk_length in 1, 2, 3, 7, 10, 13, 16, 40, 80, 128: cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) for chunk in break_up(auth_data, chunk_length): cipher.update(chunk) pt2 = b("") for chunk in break_up(ciphertext, chunk_length): pt2 += cipher.decrypt(chunk) pt2 += cipher.decrypt() self.assertEqual(plaintext, pt2) cipher.verify(ref_mac) # Decryption for chunk_length in 1, 2, 3, 7, 10, 13, 16, 40, 80, 128: cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) for chunk in break_up(auth_data, chunk_length): cipher.update(chunk) ct2 = b("") for chunk in break_up(plaintext, chunk_length): ct2 += cipher.encrypt(chunk) ct2 += cipher.encrypt() self.assertEqual(ciphertext, ct2) self.assertEqual(cipher.digest(), ref_mac) class OcbFSMTests(unittest.TestCase): key_128 = get_tag_random("key_128", 16) nonce_96 = get_tag_random("nonce_128", 12) data_128 = get_tag_random("data_128", 16) def test_valid_init_encrypt_decrypt_digest_verify(self): # No authenticated data, fixed plaintext # Verify path INIT->ENCRYPT->ENCRYPT(NONE)->DIGEST cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) ct = cipher.encrypt(self.data_128) ct += cipher.encrypt() mac = cipher.digest() # Verify path INIT->DECRYPT->DECRYPT(NONCE)->VERIFY cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.decrypt(ct) cipher.decrypt() cipher.verify(mac) def test_invalid_init_encrypt_decrypt_digest_verify(self): # No authenticated data, fixed plaintext # Verify path INIT->ENCRYPT->DIGEST cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) ct = cipher.encrypt(self.data_128) self.assertRaises(TypeError, cipher.digest) # Verify path INIT->DECRYPT->VERIFY cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.decrypt(ct) self.assertRaises(TypeError, cipher.verify) def test_valid_init_update_digest_verify(self): # No plaintext, fixed authenticated data # Verify path INIT->UPDATE->DIGEST cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) mac = cipher.digest() # Verify path INIT->UPDATE->VERIFY cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) cipher.verify(mac) def test_valid_full_path(self): # Fixed authenticated data, fixed plaintext # Verify path INIT->UPDATE->ENCRYPT->ENCRYPT(NONE)->DIGEST cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) ct = cipher.encrypt(self.data_128) ct += cipher.encrypt() mac = cipher.digest() # Verify path INIT->UPDATE->DECRYPT->DECRYPT(NONE)->VERIFY cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) cipher.decrypt(ct) cipher.decrypt() cipher.verify(mac) def test_invalid_encrypt_after_final(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) cipher.encrypt(self.data_128) cipher.encrypt() self.assertRaises(TypeError, cipher.encrypt, self.data_128) def test_invalid_decrypt_after_final(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) cipher.decrypt(self.data_128) cipher.decrypt() self.assertRaises(TypeError, cipher.decrypt, self.data_128) def test_valid_init_digest(self): # Verify path INIT->DIGEST cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.digest() def test_valid_init_verify(self): # Verify path INIT->VERIFY cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) mac = cipher.digest() cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.verify(mac) def test_valid_multiple_encrypt_or_decrypt(self): for method_name in "encrypt", "decrypt": for auth_data in (None, b("333"), self.data_128, self.data_128 + b("3")): if auth_data is None: assoc_len = None else: assoc_len = len(auth_data) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) if auth_data is not None: cipher.update(auth_data) method = getattr(cipher, method_name) method(self.data_128) method(self.data_128) method(self.data_128) method(self.data_128) method() def test_valid_multiple_digest_or_verify(self): # Multiple calls to digest cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) first_mac = cipher.digest() for x in range(4): self.assertEqual(first_mac, cipher.digest()) # Multiple calls to verify cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) for x in range(5): cipher.verify(first_mac) def test_valid_encrypt_and_digest_decrypt_and_verify(self): # encrypt_and_digest cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) ct, mac = cipher.encrypt_and_digest(self.data_128) # decrypt_and_verify cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.update(self.data_128) pt = cipher.decrypt_and_verify(ct, mac) self.assertEqual(self.data_128, pt) def test_invalid_mixing_encrypt_decrypt(self): # Once per method, with or without assoc. data for method1_name, method2_name in (("encrypt", "decrypt"), ("decrypt", "encrypt")): for assoc_data_present in (True, False): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) if assoc_data_present: cipher.update(self.data_128) getattr(cipher, method1_name)(self.data_128) self.assertRaises(TypeError, getattr(cipher, method2_name), self.data_128) def test_invalid_encrypt_or_update_after_digest(self): for method_name in "encrypt", "update": cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.encrypt(self.data_128) cipher.encrypt() cipher.digest() self.assertRaises(TypeError, getattr(cipher, method_name), self.data_128) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.encrypt_and_digest(self.data_128) def test_invalid_decrypt_or_update_after_verify(self): cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) ct = cipher.encrypt(self.data_128) ct += cipher.encrypt() mac = cipher.digest() for method_name in "decrypt", "update": cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.decrypt(ct) cipher.decrypt() cipher.verify(mac) self.assertRaises(TypeError, getattr(cipher, method_name), self.data_128) cipher = AES.new(self.key_128, AES.MODE_OCB, nonce=self.nonce_96) cipher.decrypt_and_verify(ct, mac) self.assertRaises(TypeError, getattr(cipher, method_name), self.data_128) class OcbRfc7253Test(unittest.TestCase): # Tuple with # - nonce # - authenticated data # - plaintext # - ciphertext and 16 byte MAC tag tv1_key = "000102030405060708090A0B0C0D0E0F" tv1 = ( ( "BBAA99887766554433221100", "", "", "785407BFFFC8AD9EDCC5520AC9111EE6" ), ( "BBAA99887766554433221101", "0001020304050607", "0001020304050607", "6820B3657B6F615A5725BDA0D3B4EB3A257C9AF1F8F03009" ), ( "BBAA99887766554433221102", "0001020304050607", "", "81017F8203F081277152FADE694A0A00" ), ( "BBAA99887766554433221103", "", "0001020304050607", "45DD69F8F5AAE72414054CD1F35D82760B2CD00D2F99BFA9" ), ( "BBAA99887766554433221104", "000102030405060708090A0B0C0D0E0F", "000102030405060708090A0B0C0D0E0F", "571D535B60B277188BE5147170A9A22C3AD7A4FF3835B8C5" "701C1CCEC8FC3358" ), ( "BBAA99887766554433221105", "000102030405060708090A0B0C0D0E0F", "", "8CF761B6902EF764462AD86498CA6B97" ), ( "BBAA99887766554433221106", "", "000102030405060708090A0B0C0D0E0F", "5CE88EC2E0692706A915C00AEB8B2396F40E1C743F52436B" "DF06D8FA1ECA343D" ), ( "BBAA99887766554433221107", "000102030405060708090A0B0C0D0E0F1011121314151617", "000102030405060708090A0B0C0D0E0F1011121314151617", "1CA2207308C87C010756104D8840CE1952F09673A448A122" "C92C62241051F57356D7F3C90BB0E07F" ), ( "BBAA99887766554433221108", "000102030405060708090A0B0C0D0E0F1011121314151617", "", "6DC225A071FC1B9F7C69F93B0F1E10DE" ), ( "BBAA99887766554433221109", "", "000102030405060708090A0B0C0D0E0F1011121314151617", "221BD0DE7FA6FE993ECCD769460A0AF2D6CDED0C395B1C3C" "E725F32494B9F914D85C0B1EB38357FF" ), ( "BBAA9988776655443322110A", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F", "BD6F6C496201C69296C11EFD138A467ABD3C707924B964DE" "AFFC40319AF5A48540FBBA186C5553C68AD9F592A79A4240" ), ( "BBAA9988776655443322110B", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F", "", "FE80690BEE8A485D11F32965BC9D2A32" ), ( "BBAA9988776655443322110C", "", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F", "2942BFC773BDA23CABC6ACFD9BFD5835BD300F0973792EF4" "6040C53F1432BCDFB5E1DDE3BC18A5F840B52E653444D5DF" ), ( "BBAA9988776655443322110D", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F2021222324252627", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F2021222324252627", "D5CA91748410C1751FF8A2F618255B68A0A12E093FF45460" "6E59F9C1D0DDC54B65E8628E568BAD7AED07BA06A4A69483" "A7035490C5769E60" ), ( "BBAA9988776655443322110E", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F2021222324252627", "", "C5CD9D1850C141E358649994EE701B68" ), ( "BBAA9988776655443322110F", "", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F2021222324252627", "4412923493C57D5DE0D700F753CCE0D1D2D95060122E9F15" "A5DDBFC5787E50B5CC55EE507BCB084E479AD363AC366B95" "A98CA5F3000B1479" ) ) # Tuple with # - key # - nonce # - authenticated data # - plaintext # - ciphertext and 12 byte MAC tag tv2 = ( "0F0E0D0C0B0A09080706050403020100", "BBAA9988776655443322110D", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F2021222324252627", "000102030405060708090A0B0C0D0E0F1011121314151617" "18191A1B1C1D1E1F2021222324252627", "1792A4E31E0755FB03E31B22116E6C2DDF9EFD6E33D536F1" "A0124B0A55BAE884ED93481529C76B6AD0C515F4D1CDD4FD" "AC4F02AA" ) # Tuple with # - key length # - MAC tag length # - Expected output tv3 = ( (128, 128, "67E944D23256C5E0B6C61FA22FDF1EA2"), (192, 128, "F673F2C3E7174AAE7BAE986CA9F29E17"), (256, 128, "D90EB8E9C977C88B79DD793D7FFA161C"), (128, 96, "77A3D8E73589158D25D01209"), (192, 96, "05D56EAD2752C86BE6932C5E"), (256, 96, "5458359AC23B0CBA9E6330DD"), (128, 64, "192C9B7BD90BA06A"), (192, 64, "0066BC6E0EF34E24"), (256, 64, "7D4EA5D445501CBE"), ) def test1(self): key = unhexlify(b(self.tv1_key)) for tv in self.tv1: nonce, aad, pt, ct = [ unhexlify(b(x)) for x in tv ] ct, mac_tag = ct[:-16], ct[-16:] cipher = AES.new(key, AES.MODE_OCB, nonce=nonce) cipher.update(aad) ct2 = cipher.encrypt(pt) + cipher.encrypt() self.assertEqual(ct, ct2) self.assertEqual(mac_tag, cipher.digest()) cipher = AES.new(key, AES.MODE_OCB, nonce=nonce) cipher.update(aad) pt2 = cipher.decrypt(ct) + cipher.decrypt() self.assertEqual(pt, pt2) cipher.verify(mac_tag) def test2(self): key, nonce, aad, pt, ct = [ unhexlify(b(x)) for x in self.tv2 ] ct, mac_tag = ct[:-12], ct[-12:] cipher = AES.new(key, AES.MODE_OCB, nonce=nonce, mac_len=12) cipher.update(aad) ct2 = cipher.encrypt(pt) + cipher.encrypt() self.assertEqual(ct, ct2) self.assertEqual(mac_tag, cipher.digest()) cipher = AES.new(key, AES.MODE_OCB, nonce=nonce, mac_len=12) cipher.update(aad) pt2 = cipher.decrypt(ct) + cipher.decrypt() self.assertEqual(pt, pt2) cipher.verify(mac_tag) def test3(self): for keylen, taglen, result in self.tv3: key = bchr(0) * (keylen // 8 - 1) + bchr(taglen) C = b("") for i in range(128): S = bchr(0) * i N = long_to_bytes(3 * i + 1, 12) cipher = AES.new(key, AES.MODE_OCB, nonce=N, mac_len=taglen // 8) cipher.update(S) C += cipher.encrypt(S) + cipher.encrypt() + cipher.digest() N = long_to_bytes(3 * i + 2, 12) cipher = AES.new(key, AES.MODE_OCB, nonce=N, mac_len=taglen // 8) C += cipher.encrypt(S) + cipher.encrypt() + cipher.digest() N = long_to_bytes(3 * i + 3, 12) cipher = AES.new(key, AES.MODE_OCB, nonce=N, mac_len=taglen // 8) cipher.update(S) C += cipher.encrypt() + cipher.digest() N = long_to_bytes(385, 12) cipher = AES.new(key, AES.MODE_OCB, nonce=N, mac_len=taglen // 8) cipher.update(C) result2 = cipher.encrypt() + cipher.digest() self.assertEqual(unhexlify(b(result)), result2) def get_tests(config={}): tests = [] tests += list_test_cases(OcbTests) tests += list_test_cases(OcbFSMTests) tests += list_test_cases(OcbRfc7253Test) return tests if __name__ == '__main__': import unittest suite = lambda: unittest.TestSuite(get_tests()) unittest.main(defaultTest='suite')